Contagious equine metritis (CEM) is a highly contagious venereal disease of horses caused by a fastidious, gram-negative cocobacillus. The disease is characterized by a copious water-to-mucopurulent vaginal discharge 2-10 days after breeding by an infected stallion. Shortened estrous cycle links are common and may be the only indication of endometritis in some instances. Carriers of the disease are difficult to detect but outbreaks of the disease have been reported in England, Ireland, France, Australia and in the United States. As reported by Swaney et al, American Journal of Veterinary Research, Vol. 41, January, 1980, pps. 127-132, the causative agent of contagious equine metritis has been identified as Haemophilus equigenitalis, which has ultra-structural characteristics of gram-negative bacteria. The Haemophilus equigenitalis is microaerophilic and unreactive biochemically. It does not depend on hemin (X factor) or nicotinamide adenine dinucleotide (V factor) for growth although hemin stimulates growth.
Various proposals have been made for treatment of the disease with modest success. Thus, in the article by Swaney et al, there is disclosure that streptomycin can be used against the bacteria. Further, in the article by John P. Hughes in Theriogenology, published Dec. 8, 1978, it is reported that a wide range of antibiotic and antimicrobial agents have been used either topically, parenterally or in combination at varying dose rates and over different periods of time. Included are suggestions for the use of intrauterine antiseptic solutions, washing with surgical soap, rinsing and applying 0.3% nitrofurazone ointments and the like but the most common treatment is indicated as being the intrauterine infusion of benzyl penicillin or ampicillin for a period of 3 to 5 days.
In the article by Henry J. Dabernat et al in Antimicrobial Agents and Chemotherapy, December 1980, pps. 841-843, a review of this disease is disclosed with the statement that the most active drugs are ampicillin, gentamicin, and tetracycline, although a number of other materials were tested with negative results. In an article by S. P. Sahu et al appearing in American Journal of Veterinary Research, Vol. 41, September 1980, pps. 1379-1382, there is described a review of the disease and the use of a citrate-phosphate buffer for a sugar compound to isolate and identify the bacteria but not as a method of treatment.
It is evident from this literature that there remains a need in the art for a simple, effective method for the treatment of animals infected with this disease and the present invention provides compositions and methods which are effective for this purpose.